Whoever it is, I would like to know more about how to shoot onto a medium that lacks sensitivity to absorb light.

That's a non-sequitur. 'ISO' has nothing to do with 'sensitivity to absorb light'. All ISO says is what grey scale you get for what exposure. So, 'ISOless camera' (or sensor) simply means that the camera treats all exposure levels the same, so that the decision as to which grey scale value you get for which exposure may be made at processing rather than capture time.

The Red cameras truly are ISO-less, the ISO setting just sets the tone-curve/LUT but doesn't change the raw data at all. The setting is stored as Meta-data simply to use as a starting point for setting the tone curve at playback.

Whoever it is, I would like to know more about how to shoot onto a medium that lacks sensitivity to absorb light.

That's a non-sequitur. 'ISO' has nothing to do with 'sensitivity to absorb light'. All ISO says is what grey scale you get for what exposure. So, 'ISOless camera' (or sensor) simply means that the camera treats all exposure levels the same, so that the decision as to which grey scale value you get for which exposure may be made at processing rather than capture time.

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Bob

ISO is a measure for sensitivity: how much light needed to make an exposure. Going ISOless would entail going without sensitivity aspect of the medium used to photograph.

The Red cameras truly are ISO-less, the ISO setting just sets the tone-curve/LUT but doesn't change the raw data at all. The setting is stored as Meta-data simply to use as a starting point for setting the tone curve at playback.

But not the first with that characteristic - it was typical on most MFD backs with 16 bit converters. Most CCD cameras were 'ISOless' in the sense that the term is used today. The earliest MOS ISOless cameras (in those terms) were probably the Nikon D2X and D2H (2004)

Whoever it is, I would like to know more about how to shoot onto a medium that lacks sensitivity to absorb light.

That's a non-sequitur. 'ISO' has nothing to do with 'sensitivity to absorb light'. All ISO says is what grey scale you get for what exposure. So, 'ISOless camera' (or sensor) simply means that the camera treats all exposure levels the same, so that the decision as to which grey scale value you get for which exposure may be made at processing rather than capture time.

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Bob

ISO is a measure for sensitivity: how much light needed to make an exposure.

What you said was 'sensitivity to absorb light', which it certainly isn't. For instance the 1D X is approximately twice as 'sensitive' in terms of its 'ability to absorb light' as the 5D, yet both have the same ISO set to 100 ISO. And in fact, you are wrong also aboutISO being a measure for 'how much light is needed to make an exposure'. It is not that at all, it is a mapping of exposure to grey scale and says nothing about the outcome except that you will get the specified grey value for the specified exposure.

Going ISOless would entail going without sensitivity aspect of the medium used to photograph.

Only if you choose to totally misunderstand ISO.

The word you are looking for is: Fixed ISO.

No, fixed ISO would mean that you also get the same grey scale value for the same exposure, that is not what is talked about at all.

Thank you Bob. I do not know enough to know if S Panoholic's meaning for the word is the same as your meaning for the word. Can you tell us if he or she used the word to mean the same thing as you did or was his or her use of the word just a coincidence?

Whoever it is, I would like to know more about how to shoot onto a medium that lacks sensitivity to absorb light.

That's a non-sequitur. 'ISO' has nothing to do with 'sensitivity to absorb light'. All ISO says is what grey scale you get for what exposure. So, 'ISOless camera' (or sensor) simply means that the camera treats all exposure levels the same, so that the decision as to which grey scale value you get for which exposure may be made at processing rather than capture time.

-- hide signature --

Bob

ISO is a measure for sensitivity: how much light needed to make an exposure.

What you said was 'sensitivity to absorb light', which it certainly isn't. For instance the 1D X is approximately twice as 'sensitive' in terms of its 'ability to absorb light' as the 5D, yet both have the same ISO set to 100 ISO. And in fact, you are wrong also aboutISO being a measure for 'how much light is needed to make an exposure'. It is not that at all, it is a mapping of exposure to grey scale and says nothing about the outcome except that you will get the specified grey value for the specified exposure.

Going ISOless would entail going without sensitivity aspect of the medium used to photograph.

Only if you choose to totally misunderstand ISO.

The word you are looking for is: Fixed ISO.

No, fixed ISO would mean that you also get the same grey scale value for the same exposure, that is not what is talked about at all.

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Bob

Explain why grey scale will change with exposure and what would cause that change.

The Red cameras truly are ISO-less, the ISO setting just sets the tone-curve/LUT but doesn't change the raw data at all. The setting is stored as Meta-data simply to use as a starting point for setting the tone curve at playback.

But not the first with that characteristic - it was typical on most MFD backs with 16 bit converters. Most CCD cameras were 'ISOless' in the sense that the term is used today. The earliest MOS ISOless cameras (in those terms) were probably the Nikon D2X and D2H (2004)

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Bob

Did those cameras store the ISO setting as meta-data for the raw conversion without adjusting sensor gain? I think some MF cameras may have, but the Nikon cameras don't.

Technically and properly ISO literally means 'International Standards Organisation', so an ISOless camera would mean that it doesn't comply with international standards, in this case pertaining to the scale used to describe accurately and universally for comparison purposes, the sensor's sensitivity to light. More accurately still, it measures what the imaging engine does with the available light at set steps of the scale.

Thank you Bob. I do not know enough to know if S Panoholic's meaning for the word is the same as your meaning for the word. Can you tell us if he or she used the word to mean the same thing as you did or was his or her use of the word just a coincidence?

He, or she means the same. It is about an MFD back where the ISO is just metadata, as DSPographer described.

The Red cameras truly are ISO-less, the ISO setting just sets the tone-curve/LUT but doesn't change the raw data at all. The setting is stored as Meta-data simply to use as a starting point for setting the tone curve at playback.

But not the first with that characteristic - it was typical on most MFD backs with 16 bit converters. Most CCD cameras were 'ISOless' in the sense that the term is used today. The earliest MOS ISOless cameras (in those terms) were probably the Nikon D2X and D2H (2004)

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Bob

Did those cameras store the ISO setting as meta-data for the raw conversion without adjusting sensor gain? I think some MF cameras may have, but the Nikon cameras don't.

Yes, the MFD backs did, the Nikon's don't, but are useable that way if you stick to base ISO.

Whoever it is, I would like to know more about how to shoot onto a medium that lacks sensitivity to absorb light.

That's a non-sequitur. 'ISO' has nothing to do with 'sensitivity to absorb light'. All ISO says is what grey scale you get for what exposure. So, 'ISOless camera' (or sensor) simply means that the camera treats all exposure levels the same, so that the decision as to which grey scale value you get for which exposure may be made at processing rather than capture time.

-- hide signature --

Bob

ISO is a measure for sensitivity: how much light needed to make an exposure.

What you said was 'sensitivity to absorb light', which it certainly isn't. For instance the 1D X is approximately twice as 'sensitive' in terms of its 'ability to absorb light' as the 5D, yet both have the same ISO set to 100 ISO. And in fact, you are wrong also aboutISO being a measure for 'how much light is needed to make an exposure'. It is not that at all, it is a mapping of exposure to grey scale and says nothing about the outcome except that you will get the specified grey value for the specified exposure.

Going ISOless would entail going without sensitivity aspect of the medium used to photograph.

Only if you choose to totally misunderstand ISO.

The word you are looking for is: Fixed ISO.

No, fixed ISO would mean that you also get the same grey scale value for the same exposure, that is not what is talked about at all.

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Bob

Explain why grey scale will change with exposure and what would cause that change.

You might be asking one of two separate questions there.

i) How does the the mapping between exposure and grey scale change if the ISO setting is changed? If that is the question, the answer is that the ISO standards do not dictate how that should happen, and it typically happens in one of two ways or a mixture thereof. One is that the analog gain before the ADC is changed, the second is that the mapping between the readings from the ADC and the grey scale values is changed. If exclusively the second, then the camera is what is being referred to here as 'ISOless'.

ii) How do different exposure levels result in different grey scale levels? The ADC values essentially represent photon counts. The development process maps the scale of photon counts to a grey scale.

Neither of those things intrinsically represents a change of sensitivity. The analog gain change might result in a smaller minimum signal being readable, due to lower read noise (in photoelectron terms) which could be termed a change in sensitivity, but this is a completely different thing to 'ISO' since the ISO speed ratings do not specify the minimum readable signal.

In fact it doesn't. 'ISO' is not an acronym. The nam of the organisation in English is 'the International Organisation for Standardization'.

so an ISOless camera would mean that it doesn't comply with international standards, in this case pertaining to the scale used to describe accurately and universally for comparison purposes, the sensor's sensitivity to light.

That is not what the ISO speed standards describe. They do not specify the sensor's sensitivity to light at all.

More accurately still, it measures what the imaging engine does with the available light at set steps of the scale.

Thank you Bob. I do not know enough to know if S Panoholic's meaning for the word is the same as your meaning for the word. Can you tell us if he or she used the word to mean the same thing as you did or was his or her use of the word just a coincidence?

He, or she means the same. It is about an MFD back where the ISO is just metadata, as DSPographer described.

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Bob

Well I guess he or she gets credited on a technicality, but his or her use of the word did not result in the word being commonly used, so I would say you seem to be the one to receive credit for the word being commonly used today. Now the people that don't like the word know whom to blame for it.